Androgens are derivatives of cyclopentanoperhydrophenanthrene. Endogenous androgens are C-19 steroids with two angular methyl groups. Testosterone is the primary endogenous androgen.
Endogenous androgens are responsible for the normal growth and development of the male sex organs and the maintenance of secondary sex characteristics. These effects include the growth and maturation of prostate, seminal vesicles, penis and scrotum, the development of male hair distribution, such as beard, pubic, chest and axillary hair, laryngeal enlargement, vocal chord thickening, alterations in body musculature and fat distribution. Androgens are responsible for the growth spurt of adolescence and for the eventual termination of linear growth which is brought about by fusion of the epiphyseal growth centers. Androgens such as testosterone slowly decrease as both women and men age.
In males, androgens are indicated as a replacement therapy for conditions associated with a deficiency or absence of endogenous testosterone such as primary hypogonadism and hypogonadotropic hypogonadism. Androgens may also be used to stimulate puberty in selected males with clearly delayed puberty. Testosterone therapy has also been suggested to ameliorate some of the signs and symptoms of frailty in men beyond 50 years of age (Morley et al., Gen. Geriatr. Med., 1997, 13(4):685-95).
Androgens may also be used secondarily in women with advancing inoperable metastatic (skeletal) mammary cancer who are 1 to 5 years postmenopausal. This treatment has also been used in premenopausal women who have benefitted from oophorectomy and are considered to have a hormone responsive tumor. Therapy with the androgen derivative methyltestosterone in combination with esterified estrogens has also been approved for women for the control of severe vasomotor symptoms, commonly referred to as "hot flashes".
Androgens are known to allow for increased body musculature and improved libido and energy levels. For example, while there are currently no studies proving that anabolic steroids increase lean body mass among HIV infected patients, clinical experience suggests that these agents enable many patients to gain muscle mass. Anabolic steroids seem to work best for patients who are able to do weight training. The most commonly used regimens for this therapy are testosterone enanthate or testosterone cypionate (100-200 mg intramuscularly every 2-4 weeks). However, testosterone patches for transdermal delivery can also be used. Exogenous testosterone therapy has also been suggested to produce functional improvement when combined with exercise in patients suffering from X-linked bulbospinal muscular atrophy (Goldenberg, J. N. and Bradley, W. G., J. Neurol. Sci., 1996, 135(2) 158-61). In addition, dehydroepiandrosterone-annexed vitamin C infusion treatment of a male patient suffering from chronic fatigue syndrome was suggested to effectuate the clinical control of pulmonary infection associated with chronic fatigue syndrome by fortifying the endogenous activities of both cortisol and testosterone (Kodama et al., In Vivo, 1996, 10(6) 575-84).
Androgens have also been reported to stimulate the production of red blood cells by enhancing the production of erythropoietic stimulating factor. Androgens such as oxymetholone, 200 mg orally daily, or testosterone reduce the transfusion requirement in one third of the cases of myelofibrosis, a myeloproliferative disorder characterized by fibrosis of the bone marrow, splenomegaly and leukoerthroblastic peripheral blood picture with teardrop poikilocytosis.
It has now been found that androgen therapy is useful in alleviating the symptoms associated with chronic fatigue syndrome and fibromyalgia syndrome.